Development Of Temporomandibular Disorders Research Articles

Comparative evaluation and correlation of variations in articular disc morphology as assessed by automated segmentation using deep learning on magnetic resonance imaging (MRI) images in Class II (vertical) TMD cases, Class II (horizontal) TMD cases and Class I non-TMD cases

Introduction: Temporomandibular disorder (TMD) encompasses several clinical manifestations, which are characterized by temporomandibular joint and masticatory muscle discomfort and dysfunction (TMJ). The best imaging technique for evaluating TMJ is magnetic resonance imaging (MRI), which makes it possible to see the anatomical and pathological characteristics of every joint component. In recent years, convolutional neural networks -based deep learning algorithms have been favoured because of their outstanding capability in recognizing objects in medical images. The objective of this study is to assess, compare and co-rrelate articular disc morphology by automated segmentation using deep learning on MRI images in skeletal Class II (vertical growth pattern) TMD cases as compared to skeletal Class II (horizontal growth pattern) TMD cases and Class I non-TMD cases Methods: Grading of skeletal Class II (vertical growth pattern) cases and skeletal Class II (horizontal growth pattern) cases based on severity of TMD will be carried out using diagnostic criteria for temporomandibular disorders. Bilateral sagittal as well as coronal MRI images will be obtained. A convolutional neural network (CNN) encoder-decoder named U-Net will be used to segment the articular disc on MRI. Understanding the nature of variations between Class I and both types of Class IIs will help orthodontists to better predict the potential risk for the development of TMDs and accordingly take precautions while doing treatment in such cases. Moreover, it can be used to automate TMD diagnosis and other smart applications. Conclusions: This study will aid in identifying articular disc morphology on MRI. The deep learning algorithms with effective data augmentation may perform better in MRI readings than human clinicians when using the same data, which will be advantageous for TMD diagnosis.

Anxiety associated painful temporomandibular disorders in Peruvian dental students during the major waves of COVID-19 infection: A cohort study

Abstract Aim: During the major waves of coronavirus disease 2019 (COVID-19) infection, Peru had the highest case fatality rate in the world. This situation may have caused psychological conditions with somatic consequences in students who were susceptible to infection due to exposure to infected patients. The present study was designed to investigate the association between anxiety levels and painful temporomandibular disorders in dental students from two Peruvian provinces during the major waves of COVID-19 infection. Materials and Methods: The study conducted was both longitudinal and analytical. The total population consisted of 558 dental students from Peru, with 314 from Chimbote and 244 from Trujillo. No sample size calculation was necessary as the entire student population was invited to participate. Of the 366 students who initially joined the closed cohort, only 204 remained at the end of the study. During the first and second waves of COVID-19 infections, the Zung anxiety diagnostic test and the diagnostic criteria for painful temporomandibular disorder (DC/TMD) triage questionnaire were used to assess anxiety levels. The study also evaluated variables such as sex, age, marital status, academic year of study, area of residence, housing type, and occupation. The study employed statistical analysis to determine the relative risk (RR) of painful TMD incidence during the first and second waves of COVID-19 infections. A logit model was also used to determine the presence of painful TMD, with odds ratio (OR) as the measure. The statistical significance level was set at P < 0.05. Results: During the initial wave of COVID-19 infections, 50% (95% CI: 43.1–56.9%) of the 204 students experienced anxiety, while 26.5% (95% CI: 20.4–32.6%) reported TMD. Furthermore, those who exhibited anxiety were eight times more likely to develop TMD (OR = 8.88, 95% CI: 3.95 - 19.97). In the second wave, 62.3% (95% CI: 55.6–69.0%) of students reported anxiety, and 86.3% (95% CI: 81.6–91.0%) reported TMD. Additionally, individuals with anxiety were found to have a significantly higher likelihood of developing painful TMD, with a nine-fold increase in risk (OR = 9.87, 95% CI: 5.08–19.19). The cohort of students exposed and not exposed to anxiety during the first and second waves of COVID-19 infection showed a 4.58 times higher risk (95% CI: 2.61–8.03) of developing painful TMD due to anxiety. Conclusion: Between the first and second waves of COVID-19 infection, the prevalence of anxiety and painful temporomandibular disorder (TMD) increased among dental students. This establishes anxiety as a significant predisposing factor for the development of painful TMD over time.

Etiologic Factors of Temporomandibular Disorders: A Systematic Review of Literature Containing Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) from 2018 to 2022.

This study aims to conduct a systematic analysis of literature published between 1 January 2018 and 1 September 2022, exploring factors influencing the progression or development of temporomandibular disorders (TMD), diagnosed using the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) or Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Three electronic databases were reviewed to identify papers that examined TMD factors using DC/TMD or RDC/TMD. Inclusion criteria encompassed original research published in English between 1 January 2018 and 1 October 2022, online, and complete DC/TMD or RDC/TMD studies on human participants aged 18 or older. Two authors independently assessed the risk of bias using The Joanna Briggs Institute (JBI) Analytical cross-sectional studies' Critical Appraisal Tool. Of 1478 articles, 11 were included. The studies revealed strong associations between TMD and factors such as female, poor sleep quality, depression, oral parafunction, anxiety, somatization, and anatomical features. However, variables such as education, living conditions, socioeconomic status, marital status, chronic pain, and stress did not exhibit statistically significant correlations. Based on the obtained data, it can be concluded that the causes of TMD are largely related to psychological factors, which supports the biopsychosocial theory of the disorder.

Relationship Between Occlusal Factors and Temporomandibular Disorders: A Systematic Literature Review.

Temporomandibular disorders (TMD) originate from various components within the temporomandibular joint (TMJ), causing an impact on the masticatory muscles, the joint itself, and associated structures. They are a widely prevalent issue across the world. According to epidemiological research, up to 50% of adults in the population have TMD-related symptoms. The objective of this work was to analyze the existing scientific literature regarding the association between malocclusion classes, bruxism, and tooth loss in relation to the etiology of TMD. This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 analysis protocol. For the development of the question focus, the population, intervention, control, and outcomes (PICO) study design protocol was used. The question in focus according to the PICO format was: "Do malocclusion, tooth loss, and bruxism contribute to temporomandibular disorders?". The review was performed with articles from PubMed, Web of Science, and Google Scholar databases according to the specified inclusion and exclusion criteria. The included articles were not older than five years. The risk of bias was assessed in the included studies by using the Cochrane Risk-of-bias 2 (RoB-2) tool. Out of a total of 32 results received, 21 articles were chosen according to the established criteria after conducting a review and analysis of their full texts. The article search sequence was presented in the PRISMA 2020 flow diagram, and the outcomes of the chosen articles were presented. The literature results revealed a relationship between occlusion and the development of TMD. The influence of occlusal factors on the TMJ was explained by an examination of joint anatomy and symptoms related to TMD. This study revealed variations in TMJ factors across different malocclusion classes. Additionally, it was observed that the occurrence and attributes of TMD are influenced by the number of tooth loss quadrants and the frequency of missing teeth. Furthermore, a correlation was found between bruxism and the symptoms of TMD, including myofascial pain, disc displacement, arthralgia, and muscle disorders. This literature review provides comprehensive information on the relationship between malocclusion classes, bruxism, tooth loss, and TMDs. This prompts healthcare professionals to prioritize patients' occlusal assessment and TMJ condition.

Prevalence of temporomandibular disorders in juvenile idiopathic arthritis evaluated with diagnostic criteria for temporomandibular disorders: A systematic review with meta-analysis.

Juvenile idiopathic arthritis (JIA) is a very common systemic inflammatory rheumatic disorder affecting the musculoskeletal system in children below 16 years of age. Joint inflammation and tissue destruction is the prime characteristic of the disease. Along with the systemic involvement in the long joints, several studies are mentioning the increased association of temporomandibular disorders (TMDs) in JIA. This current systematic review intends to find the prevalence rate of TMD in JIA-affected individuals as compared to healthy controls. We have searched in PubMed, Scopus and Ovid SP for articles published between the timeframe 1 January 1990 and 1 June 2023. All the searched articles were subjected to the Population, Exposure, Comparison, and Outcome model (PECO) based on which inclusion or exclusion is carried out. Participants (P) are children below 18 years of age, Exposure (E) is children or adolescents with a diagnosis of JIA, Comparator is age and gender-matched healthy controls who has no JIA or any systemic disorder, Outcome (O) is the prevalence of TMD. Only the studies that evaluated TMD using diagnostic criteria for evaluation of TMD (DC/TMD) were included in the analysis. We have set the exclusion to the following reasons- diagnostic sensitivity studies, case reports, and systematic reviews. The software Review Manager Version 5.4 (Cochrane Collaboration) was used to perform the pooled analysis. We measured the risk ratio (RR) between the two groups (JIA and no JIA) for the outcome TMD. The pooled total included subjects were 366 in this review with an established diagnosis of JIA as evaluated by DC/TMD. The overall effect of the pooled data suggests that there is a significant difference in the TMD prevalence in the JIA group when compared to the control, results suggest that TMD is more prevalent in the JIA group RR 3.86; 95% CI [2.59, 5.76]. Overall, based on the data we can suggest a positive relationship between JIA and TMD, hence presence of JIA can be a risk factor for the development of TMD. The sensitivity of DC/TMD is low when compared to magnetic resonance imaging.

Relation between Condyle Horizontal Angle and Intercondylar Angle with Disc Displacement in Patients with Temporomandibular Joint Disorders: An MRI Evaluation.

Internal derangement (ID) is the most common cause of temporomandibular disorders (TMDs) and extensively affects the articular disc function. The anterior disc displacement is among the most important findings in ID. Knowledge about the etiology of this condition is imperative, and the role of structural parameters in the development of TMDs has not been well evaluated. This study aimed to assess the relationship between condylar angulation and intercondylar angle with anterior disc displacement in patients with TMD using magnetic resonance imaging (MRI). This case-control study evaluated 31 temporomandibular joints with internal derangement and 57 normal joints. The data retrieved from MRI included disc position in the open mouth (normal, anterior disc displacement with a reduction (DDWR) and without reduction (DDWOR), and posterior displacement (PD)), horizontal condylar angle categorized as normal (10 to 30° angle) and abnormal (<10° and >30°), and intercondylar angle. Chi-square test, T-test, and Fisher's exact were done to assess the relationship between horizontal condylar angle and intercondylar angle in patients with TMDs with DDWR and DDWOR compared with the control group. Patients with DDWR and DDWOR had higher odds of abnormal horizontal condylar angle, particularly >30° angle, which was a significant correlation (odds ratio of 0.19 and 8.3, respectively). The intercondylar angle in the patients with disc displacement was significantly smaller compared to the control group. Disc displacement was correlated with abnormal horizontal angle (particularly < 30) and smaller intercondylar angle compared with the control group.

Prevalence of temporomandibular disorders (TMD) in bleeding disorders: A systematic review with meta-analysis.

Haemophilia A, B and von Willebrand disease are the most common bleeding disorders. There is an increased tendency of spontaneous bleeding into joints resulting in intra-articular infection. It is believed that Temporomandibular Joint (TMJ) can be affected in a similar manner which can further lead to limited mouth opening and ankylosis. The association between bleeding disorders (BD) and development of temporomandibular disorders (TMD) is poorly understood. This systematic review intends to evaluate the association of TMD in individuals with inherited bleeding disorders as compared to healthy controls. PubMed, Ovid SP and Google Scholar were searched for articles published between the times of inception to 1 May 2023. All the articles were subjected to Population, Exposure, Comparison and Outcome model (PECO) based on which inclusion and exclusion criteria were applied. Participants (P) is children, adults or adolescents; Exposure (E) is children, adults or adolescents with a diagnosis of Haemophilia or bleeding disorder (BD); Comparator (C) is age and gender-matched healthy controls who do not have Haemophilia or bleeding disorder; Outcome (O) is prevalence of any signs or symptoms (clinical, radiographic) that is suggestive of temporomandibular disorder (TMD). Studies showing the prevalence of TMD are included for qualitative analysis. Only the studies which provided data of the prevalence of TMD in both the groups (BD and healthy controls) were included in the quantitative analysis. TMD diagnosis can be by clinical signs and symptoms, radiographic criteria, Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) or any other imaging criteria (MRI). We have set the exclusion criteria as articles without a control group, diagnostic sensitivity studies, case reports and systematic reviews and narrative reviews. The software Review Manager version 5.4 (Cochrane Collaboration) was used to perform the pooled analysis. We measured the risk ratio (RR) between the two groups (BD and healthy controls) for the outcome TMD. A total of seven studies are included for qualitative analysis of data. The age of the population (BD and control) in the included studies ranged between 2 and 57 years. The prevalence of TMD in individual studies varied from 2% to 77%, and controls in the individual studies varied from 2% to 14%. Among the included studies, only clinical signs, symptoms and history were taken into consideration in four studies. Four studies were included for meta-analysis, the pooled result of the four studies suggests there is no significant difference in the prevalence of TMD in BD and control group (p value = .11, RR 2.19; 95% CI [0.84, 5.73]). This systematic review and meta-analysis elicits no association between bleeding disorders and increased prevalence of TMD.

Association of Serum Vitamin D Level with Temporomandibular Disorder Incidence: A Retrospective, Multi-Center Cohort Study Using Six Hospital Databases.

The relationship between serum vitamin D levels and temporomandibular disorders (TMDs) remains unclear. Therefore, this study aimed to investigate the association between serum 25-hydroxyvitamin D (25[OH]D) levels and TMD incidence using large-scale health data. Clinical data from the electronic health records of six secondary or tertiary hospitals in Korea were used to evaluate the relationship between serum 25(OH)D levels and TMD incidence. The data were converted to the Observational Medical Outcomes Partnership Common Data Model. A cohort study was designed using the Cox proportional hazards model to examine the hazard ratio (HR) of TMD development after propensity score matching (PSM). An aggregate meta-analysis of the HR was subsequently performed. After 1:4 PSM, a target group with deficient 25(OH)D levels (<20 ng/mL) (N = 34,560) and comparator group with non-deficient 25(OH)D levels (≥20 ng/mL) (N = 47,359) were pooled from six hospital databases. HR meta-analysis demonstrated a significant association between deficient 25(OH)D levels and TMD incidence (pooled HR: 1.50; 95% confidence interval: 1.07-2.12). In conclusion, deficient 25(OH)D levels were found to be associated with an increased TMD risk. Therefore, vitamin D deficiency is a potential risk factor for TMD development.

Does dental rehabilitation under general anaesthetic contribute to the development of temporomandibular disorders in children and adolescents? A scoping review.

Temporomandibular disorders (TMDs) have multiple aetiological factors. Although some evidence suggests invasive and lengthy dental procedures may contribute towards TMD development, there is a relative paucity in the literature regarding an association between elements of paediatric dental general anaesthesia (pDGA) and TMDs. This review aims to consider the impact of dental rehabilitation (and its constituent elements) performed under general anaesthesia on the development of TMDs in childhood and adolescence and identify theories and/or gaps in knowledge which may benefit from future research. Due to the need to preliminarily examine the nature and extent of the current evidence base, a scoping review approach was chosen. The review was conducted based on the framework provided by the methodological working group of the Joanna Briggs Institute (JBI) for conducting systematic scoping reviews. Electronic databases MEDLINE, Embase, Scopus, Web of Science and Cochrane Library were searched as well as the grey literature using OpenGrey, Nexis, Ethos, Google Scholar and ProQuest, with eligible studies uploaded onto Zotero (Mac Version 5.0.96.2). A total of 810 records were identified. After removing duplicates and those not available in English, 260 were identified for title and abstract screening. Seventy-six records underwent full-text review of which only one met the broad inclusion criteria. The most common reasons for exclusion were no specific relation to general anaesthesia, not specifically relating to dental treatment and only being concerned with TMD management. The included study found that while development of TMDs following dental rehabilitation under GA did occur in children, whether the problems caused by treatment were exacerbated by other elements of the pDGA process remains unknown. This review has confirmed a distinct paucity of research in this field. While there is no current tangible scientific evidence that common and routine dental procedures lead to TMD, the literature shows that alterations to any one or a combination of critical factors can contribute to TMD development, which may be collectively exacerbated by iatrogenic macrotrauma during the pDGA process. We have highlighted elements of pre-, peri- and post-operative pDGA, alongside biopsychosocial factors, which may contribute to TMD development in childhood and adolescence and may benefit from future research.

Influence of TRPV1 on Thermal Nociception in Rats with Temporomandibular Joint Persistent Inflammation Evaluated by the Operant Orofacial Pain Assessment Device (OPAD).

Temporomandibular joint (TMJ)-associated inflammation contributes to the pain reported by patients with temporomandibular disorders (TMD). It is common for patients diagnosed with TMD to report pain in the masticatory muscles and temporomandibular joints, headache, and jaw movement disturbances. Although TMD can have different origins, including trauma and malocclusion disorder, anxiety/depression substantially impacts the development and maintenance of TMD. In general, rodent studies on orofacial pain mechanisms involve the use of tests originally developed for other body regions, which were adapted to the orofacial area. To overcome limitations and expand knowledge in orofacial pain, our group validated and characterized an operant assessment paradigm in rats with both hot and cold stimuli as well mechanical stimuli. Nevertheless, persistent inflammation of the TMJ has not been evaluated with this operant orofacial pain assessment device (OPAD). We characterized the thermal orofacial sensitivity for cold, neutral, and hot stimuli during the development of TMD using the OPAD behavior test. In addition, we evaluated the role of transient receptor potential vanilloid 1 (TRPV1) expressing nociceptors in rats with persistent TMJ inflammation. The experiments were performed in male and female rats with TMJ inflammation induced by carrageenan (CARR). Additionally, resiniferatoxin (RTX) was administered into the TMJs prior CARR to lesion TRPV1-expressing neurons to evaluate the role of TRPV1-expressing neurons. We evidenced an increase in the number of facial contacts and changes in the number of reward licks per stimulus on neutral (37°C) and cold (21°C) temperatures. However, at the hot temperature (42°C), the inflammation did not induce changes in the OPAD test. The prior administration of RTX in the TMJ prevented the allodynia and thermal hyperalgesia induced by CARR. We showed that TRPV-expressing neurons are involved in the sensitivity to carrageenan-induced pain in male and female rats evaluated in the OPAD.

Economic inequalities and temporomandibular disorders: A systematic review with meta-analysis.

Temporomandibular disorders (TMDs) are a common and debilitating condition that affects millions of people globally. Despite extensive research on TMDs, the exact causes of these conditions remain unclear. However, various factors, including genetics, injury and stress, have been implicated in their development. In addition to these traditional risk factors, the literature suggests that socioeconomic status (SES) may also play a role in the development and progression of TMDs. By synthesizing the available evidence, this review will provide a comprehensive understanding of the role of SES in TMDs and will inform the development of targeted interventions to reduce the burden of these disorders among individuals with lower SES. We conducted this systematic review followed the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020. PubMed, Scopus and Lilacs were searched using the terms: ((socio-economic status OR economic status) AND (temporomandibular disorders OR temporomandibular joint) from the inception until February 10, 2023. We applied the following questions: (P) Participants consisted of human subjects. (E) The Exposure consisted of low economic stats. (C) The Comparison: subjects reporting low economic status were compared to subjects reporting medium-high economic status. (O) The Outcome consisted of TMDs diagnosis. Review Manager version 5.2.8 (Cochrane Collaboration; 2014) software was applied to perform the pooled analysis. The included subjects in this review were 14 607. Among them, 631 reported a low economic income, 1880 a medium-high economic income, 4617 were blue-collar workers and 7478 were white-collar workers or entrepreneurs. Among those reporting a low economic income or belonging to the blue-collar workers 12.93% (679/5248) presented sign/symptoms of TMD or a diagnosis of TMD whereas 10.6% (997/9358) of those with a high economic income/white-collar worker. We observed a slightly higher prevalence of TMD among individuals with a low economic income Further research is needed to better understand this relationship and to develop effective interventions to reduce the burden of TMD among individuals with low income.

Comparison of imaging findings of 714 symptomatic and asymptomatic temporomandibular joints: a retrospective study

BackgroundThe correlation between temporomandibular disorders (TMD) and imaging features remains unclear. This study compared the cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) features in the temporomandibular joints (TMJs) with and without TMD symptoms.MethodsThe participants were recruited from the TMJ Diagnosis and Treatment Center from March 2022 to September 2022. Condylar morphology and condylar position were evaluated by CBCT. Disc morphology, disc position, and joint effusion were evaluated by T2-weighted image of MRI. The Chi-Square test and binary logistic regression analysis were carried out.ResultsEighty-two patients with bilateral symptoms, 196 patients with unilateral symptoms, and 79 asymptomatic participants received MRI and CBCT examination. There were significant differences in the distribution of sex, age, condylar morphology, condylar position, disc morphology, disc position, and joint effusion in symptomatic and asymptomatic TMJs (P < 0.05), which showed a positive correlation with symptoms (P < 0.05). In multiple logistic regression, 19–30-year-age group, > 30-year-age group, abnormal condylar morphology, posterior condylar position, disc displacement with reduction (DDWR), and disc displacement without reduction (DDWoR) were found to be statistically significant (P < 0.05). The odds of having symptomatic TMJ were 1.952 higher in the 19–30-year-age group and 1.814 higher in the > 30-year-age group when compared to those aged ≤ 18-year-age group. The odds of having symptomatic TMJ were 2.360 higher in persons with abnormal condylar morphology when compared to those with normal condylar morphology. The odds of having symptomatic TMJ were 2.591 higher in persons with posterior condylar position when compared to those with the normal condylar position. The odds of having symptomatic TMJ were 2.764 higher in persons with DDWR and 4.189 higher in persons with DDWoR when compared to those with normal disc position. The area under the curve of the model was 0.736 ± 0.019 (95% CI 0.700–0.773, P = 0.000), which indicated that the model has a good fitting effect.ConclusionsThe imaging findings of TMJs were significantly different between symptomatic and asymptomatic TMJs. TMD is affected by multiple factors including > 19-year-age, abnormal condylar morphology, posterior condylar position, DDWR, and DDWoR, which could be risk factors for the development of TMD symptoms.Trial registration This study was retrospectively registered on 28/03/2022 and endorsed by the Ethics Committee of Affiliated Stomatology Hospital of Guangzhou Medical University (LCYJ2022014).

The influence of over-erupted third molar on the temporomandibular joint and related imaging research

Among the causes of temporomandibular disorders, occlusal factors have long been considered to play an important role in the occurrence and development of temporomandibular disorders, in which the third molar is extended to form intrusive contact with the opposite second molar, which is common in clinical practice and often accompanied by the symptoms and signs of TMD. This article briefly reviews the effect of third molar elongation on the morphology of temporomandibular joint.

Effect of the forward head syndrome in the development of temporomandibular disorders

Bad habits, such as poor posture during the use of technological devices, poor abdominal control and oral breathing pattern can lead to a forward head position, which has important implications for the entire future of the individual, especially at the stomatognathic system. There is a strong association between temporomandibular disorders and forward head syndrome. Where the muscular component is the main affected, with the appearance of more trigger points at the level of the sternocleidomastoid muscles, upper trapezius, rectus capitis posterior and upper oblique capitis. Degenerative changes in the temporomandibular joint have been observed, but evidence is still lacking to ensure that Forward Head Syndrome is the etiological factor.

Evaluation the relationship between polymorphism of galactose mutarotase gene by creating jaw sound in patients with temporomandibular disorder (TMD)

Objective: One of the concerns of dentists is the referral of patients with temporomandibular prob- lems. Temporomandibular joint disorders (TMD) is a complex multifactorial clinical problem that involves masticatory muscles, temporomandibular joint and related structures. This complication is one of the three common chronic pains after headache and low back pain, which can manifest as pain in the temporoman- dibular region and limitation in joint movements, or even as clicking, crepitus, and popping sounds during temporomandibular joint movements. For the first time, the american association for oral pain (AAOP) proposed the role of genetic factors in the development of TMD. It is thought that a complex disorder such as TMD is multidimensional and can be subjected to environmental conditions as well as multiple gene polymorphisms. Identification of single nucleotide polymorphisms in the human genome can play an important role in clinical setting for diagnosis, prognosis and therapeutic interventions in various diseases including TMD. The aim of this study was to evaluate the relationship between polymorphism of galactose mutarotase gene by creating jaw sound in patients with temporomandibular disorder in a population with high similarity to the whole Iranian population and using the results in prevention and targeted treatment of affected patients.&#x0D; Study Design: 101 patients with TMD using DC/TMD criteria among those referred to Tehran University School of Dentistry and 103 healthy subjects for TMD that have age and gender matched were selected to control groupfrom those referring to the Oral and Maxillofacial Diseases and Oral and Maxillo- facial Pain departments. Blood samples were taken in 5cc and DNA extracted from the blood of both groups by applying the technique PCRARMS in terms of polymorphism rs4776783 in Galm gene were Compared.&#x0D; Results: 101 patients with TMD along with 103 healthy individuals without a history of TMD were evaluated to investigate rs4776783 polymorphism in GALM gene. The average age of the patients was 35.92, and 21 were men and 80 were women. According to the questionnaire, 61 people felt the sound in their jaw while moving. On the other hand, according to the TMD/DC criterion, the number of people who have crepitus in the right and left jaws is equal. The average age of the patients was 35.92, and 21 were men and 80 were women. According to the questionnaire, 61 people felt the sound in their jaw while moving. On the other hand, according to the TMD/DC criterion, the number of people who have crepitus in the right and left jaws is equal. The low prevalence of crepitation with p=0.734 has a significant relationship with the genotype of people.&#x0D; Conclusion: This study showed that there is a significant relationship between the rs4776783 poly- morphism in Galm gene and the occurrence of temporomandibular disorder (TMD), jaw sound and pain in many masticatory muscles such as lateral pterygoid and temporal. Therefore, it can be concluded that TMD has a genetic basis.

Associations between obstructive sleep apnea and painful temporomandibular disorder: a systematic review.

The relationship between obstructive sleep apnea (OSA) and diverse types of pain conditions have been proposed. However, no consensus on the relationship between OSA and painful temporomandibular disorders (TMDs) has been established. Therefore, this systematic review has been conducted to review the existing literatures and provide comprehensive synthesis of such literatures about OSA and painful TMDs using the evidence-based methodology. A literature search was conducted using two electronic databases, Scopus, and PubMed. Risk of bias was assessed using the risk-ofbias assessment tool for non-randomized study version 2.0. A total of 158 articles were screened from the initial search and eventually, 5 articles were included in this systematic review. One study adopted both the longitudinal prospective cohort and case-control designs and other 4 articles adopted the cross-sectional design. Two studies employed polysomnography (PSG) for the diagnosis of OSA and mentioned the results from the PSG. All crosssectional studies demonstrated higher OSA prevalence among patients with TMD, and one cohort study suggested OSA as a risk factor for TMD. OSA appears to have potential influences on the development of TMD; however, the role of TMD in the development of OSA remains to be unknown owing to the lack of high-quality evidences.

Mischievous mandibular third molars camouflaging temporomandibular joint disorders.

ObjectivesThe aim of this study was to observe the relationship between impacted mandibular third molars and development of temporomandibular joint (TMJ) disorders. Knowledge of the factors that have an adverse effect on the TMJ is necessary for proper diagnosis, treatment, and prognosis of TMJ disorders.Materials and MethodsThe study was performed on 80 patients aged between 20 and 60 years with impacted mandibular third molars, over a period of two months. The patients were examined clinically and radiologically to determine the type of impaction and detect the associated TMJ symptoms or disorders.ResultsIn the 80 patients, 63.8% (51/80) of TMJ disorders were found in the horizontal group, 46.3% (37/80) in the mesioangular group, 42.5% (34/80) in the distoangular group, and 30.0% (24/80) in the vertical group of impacted mandibular third molars.ConclusionThe study concluded that type of impacted mandibular third molar is factor in the development of temporomandibular disorders.

PREVALENCE OF TEMPOROMANDIBULAR DISORDERS AMONG ORTHODONTIC PATIENTS (CROSS-SECTIONAL CLINICAL SURVEY)

Orthodontic treatment as a risk factor for the development of temporomandibular disorders (TMD) has been a controversy in literature. The aim of this study was to evaluate the prevalence of TMD, as defined in the Diagnostic Criteria (DC)/TMD Axis II, among orthodontic patients. A cross-sectional study (N=180) consisted of 3 groups: 60 control patients seeking orthodontic consultation, 60 patients undergoing orthodontic treatment for 3-5 months, 60 patients undergoing orthodontic treatment for 10-14 months. Patients answered a structured questionnaire that rated their oral parafunctions according to the Oral Behavior Checklist (OBC), pain intensity levels according to the Graded Chronic Pain Scale (GCPS), jaw functional limitations according to the Jaw Functional Limitation Scale 20 (JFLS-20), psychosocial factors (PHQ-9) and somatization levels (PHQ-15). The Chi Square test showed a statistically significant difference p-value=0.001 among both active orthodontic groups (3-5 months/10-14 months) regarding masticatory limitation (53.3%), vertical mobility limitation (41.7% for 3-5 months and 55.0% 10-14 months) and verbal &amp; emotional expression limitation (53.3% 3-5 months and 66.7% 10-14 months). The findings revealed that as orthodontic treatment progresses, the limitation increases. Moreover, no statistical significance was observed between the three groups regarding oral parafunctional habits, chronic pain levels, psychosocial status and somatization. Orthodontic treatment is not a major factor associated with the symptoms of the TMD. Further prospective studies are needed to evaluate the true role of orthodontic treatment in the development of TMD.

Severity Patterns of Temporomandibular Disorders in Young Adults with Suspected Clinical Features

Objective: Temporomandibular disorders (TMD) being progressive disorder having relatively higher prevalence in young adults necessitates early recognition in order to prevent development of established TMD. Method: Using a structured proforma and the method of interview, data were collected from 162 subjects for the frequency of severity pattern of Temporomandibular joint disorders in young adults with suspected clinical features .TMD were classified as mild ,moderate, severe and individuals having no TMD. According to Fonseca’s questionnaire the severity was determined from collective score earned from the response of the patient. TMD was clinically classified as none if the score ranged between 0-15 points, mild if 20-40 points, moderate if 45-65 points and severe if 70-100 points. Score was obtained from response of the patient. Results: Study revealed that out of 162 patients with symptoms 16.0% were categorized as having no TMD, 40.15% as having mild TMD, 35.2% with moderate TMD and 8.6% representing severe TMD. Conclusion: The most significant category of the TMD severity pattern in the young adults of this study was the mild level of temporomandibular disorder. Subjects with moderate level of TMD according to Fonseca’s questionnaire should be referred to the specialist clinic for the treatment of established TMD. Keywords: Temporomandibular disorder (TMD), Pain, Fonseca questionnaire

Sociodemographic trends in a UK temporomandibular joint disorder clinic.

Introduction Temporomandibular disorders (TMD) are a common source of facial pain, resulting from an interaction of biopsychosocial factors. However, social risk factors related to TMD have been researched very little, particularly in patients attending a tertiary care service.Aims To review sociodemographic trends among patients referred to a UK tertiary TMD clinic for specialist management. To provide an insight into the sociodemographic risk factors associated with TMD in patients referred for specialist input and to discuss the surrounding literature.Methods Retrospective review of notes of patients referred to a UK tertiary TMD clinic. Trends in areas of deprivation from which patients came from were quantified into deciles using the English Multiple Indices of Deprivation.Results The mean age of patients was 41.1 years, with women being overrepresented compared to men. Most patients were referred by their general dental practitioner, although a variety of secondary care specialties also referred to this service. A disproportionate number of patients came from the highest decile of deprivation, a trend seen throughout the entire sample and in patients seen by dental professionals specifically. There was no apparent association between this and longer symptom duration.Conclusion Women and those from areas with the highest levels of deprivation were overrepresented in this tertiary clinic setting. Dentists should maintain an awareness of the risk factors for TMD development as well as those which may complicate its management in cases requiring specialist input.